3-amino-isothiazoles, derivatives thereof and processes for the production thereof

ABSTRACT

3-Amino-isothiazoles and derivatives thereof of the formula: OR A SALT THEREOF, WHEREIN R2 and R3 are the same or different and are hydrogen, unsubstituted or substituted aralkyl, unsubstituted or substituted aryl or an unsubstituted or substituted aliphatic moiety, or R2 and R3 are both alkyl linked together to form an anellated five- to seven-membered unsaturated or saturated, unsubstituted or substituted ring system, X is hydrogen or -CO-R1, and R1 is unsubstituted or substituted aralkyl, unsubstituted or substituted aryl or an unsubstituted or substituted aliphatic moiety, are produced by reacting a compound of the formula: WHEREIN R1, R2, and R3 are as above defined, or a salt thereof, with at least a twice-molar quantity of hydroxylamine in the presence of a water-miscible organic solvent at an elevated temperature, and the N-acylamines thus formed are optionally hydrolyzed, optionally without intermediate isolation. The 3-amino-isothiazoles and derivatives so produced are useful for their fungicidal activity and may be used in treating humans, animals and plants against various fungal infections.

United States Patent Biishagen is] 7 3,692,795 51 Sept. 19, 1972 I54] 3-AMINO-ISOTI-IIAZOLES,

DERIVATIVES THEREOF AND PROCESSES FOR THE PRODUCTION THEREOF [72] Inventor: Horst Biishagen, Haan, Germany [73] Assignee: Farbenfabriken Bayer Aktiengesellschaft, Leverkusen, Germany 221 Filed: Sept. 12,1969

21 Appl.No.: 857,580

[30] 1 Foreign Application Priority Data Sept. 17, 1968 Germany ..P 17 95 344.5

[52] U.S. Cl. .....260/305, 260/306.8 F, 260/306.8 A, 260/327 R, 424/270 [5 1] Int. Cl. ..C07d 91/46 [58] Field of Search ..260/304 [56] References Cited OTHER PUBLICATIONS Fries et al., Chem. Abstracts, 21:26928 (1927). Goerdeler et al., Chem. Abstracts, 58:13946g (1963). Stolle et al., Chem. Abstracts, 20:7636 (1926).

Primary ExaminerAlex Mazel Assistant Examiner-R. J. Gallagher Attorney-Jacobs & Jacobs 5 7 ABSTRACT 3-Amino-isothiazoles and derivatives thereof of the formula:

hydrogen or COR, and R is unsubstituted or substituted aralkyl, unsubstituted or substituted aryl or an unsubstituted or substituted aliphatic moiety, are produced by reacting a compound of the formula:

in s

N-COR wherein R R and R are as above defined, or a salt thereof, with at least a twice-molar quantity of hydroxylamine in the presence of a water-miscible organic solvent at an elevated temperature, and the N- acylamines thus formed are optionally hydrolyzed, op-

ti n l w'tho ti ermediate is 1 tion.

e amino-iiiot i iazoles and ei ivatives so produced are useful for their fungicidal activity and may be used in treating humans, animals and plants against various fungal infections.

6 Claims, No Drawings formula:

or a salt thereof, wherein R and R are the same or different and are hydrogen, unsubstituted or substituted aralkyl, unsubstituted or substituted aryl or an unsubstituted or substituted aliphatic moiety, or R and R are both alkyl linked together to form an anellated five.- to seven-membered unsaturated or saturated, unsubstituted or substituted ring system, X is hydrogen or CO-R, and R is unsubstituted or substituted aralkyl, unsubstituted or substituted aryl or an unsubstituted or substituted aliphatic moiety, are obtained when a compound of the formula:

. ri-coni wherein R, R and R are as above defined, are reacted with at least a twice-molar quantity of hydroxylamine, in the presence of a water-miscible organic solvent, at an elevated temperature, and the N- acylamines thus formed are optionally hydrolyzed, optionally without intermediate isolation.

The compounds of the present invention are useful for the fungicidal activity they exhibit and thus may be I used in treating humans and animals for fungal infections and may also be used to treat plants for infections pathogenic to plant life.

Preferred compounds according to the present invention are those of Formula (II), wherein R and R are the same or different and are unsubstituted or substituted aralkyl, unsubstituted or substituted aryl, an unsubstituted or substituted aliphatic moiety, or when R is as above defined, R can be hydrogen or when R is unsubstituted or substituted aryl or an unsubstituted or substituted aliphatic moiety, R can be hydrogen, or R and R are both alkyl linked together to form an anellated fiveto seven-membered unsaturated or saturated, unsubstituted or halogen, alkyl, alkoxy or nitro substituted ring system, provided that if R and R are linked to form a benzene ring, said benzene ring is substituted by at least one halogen, alkyl, alkoxy or nitro, X is hydrogen or '--CO-R, and R is unsubstituted or substituted aralkyl, unsubstituted or substituted aryl or an unsubstituted or substituted aliphatic moiety, and wherein the salts are inorganic acid salts.

When any of R, R or R are an unsubstituted or substituted aliphatic moiety, it is preferred that such moiety be a straight or branched chained one of one to eight carbon atomsand preferably of one to four carbon atoms. The preferred substituents are halogen, particularly fluorine, chlorine or bromine, or alkoxy, preferably of one to four carbon atoms. The aliphatic moieties include those having double or triple bonds, that is they embrace not only the alkyls but the alkenyls and the alkinyls of one to eight carbon atoms and especially one to four carbon atoms which may be substituted as above noted. In addition, the aliphatic moieties include cycloaliphatic moieties of five to seven carbon atoms in the ring.

When any of R, R, or R is an unsubstituted or substituted aralkyl, it is preferred that the alkyl portion thereof be of one to four carbon atoms and preferably one to two carbon atoms. It is preferred that the aryl portion preferably contain a phenyl radical. The preferred substituents are halogen, especially fluorine, chlorine or bromine, lower alkyl, preferably of one to four carbon atoms or lower alkoxy also preferably of one to four carbon atoms.

' When any of R, R, or R are unsubstituted or substituted aryl, it is preferred that such aryl moieties contain up to 10 carbon atoms in the ring system. The preferred aryl moiety is phenyl which can carry up to two identical or different substituents. The preferred substituents are halogen, preferably fluorine, chlorine When both R and R3 are alkyl, they may be linked together to form an anellated ring. Such anellated ring may be substituted by one or more halogen atoms, i.e., fluorine, chlorine, bromine or iodine, alkyl preferably of one to four carbon atoms, alkoxy preferably of one to four carbon atoms or nitro. It is preferred that when a nitro group is present that only one such nitro group should be present on the anellated ring.

The 3-acylimino-3l-l-1,2-benzodithioles (I) used as starting materials are either known or can be obtained by known processes ]Chem. Ber. 101, 2472 (1968)].

The process according to the present invention may be illustrated by the following reaction mechanism;

s Nmon s Y -s; -H20 -OOCH3 --s s 1 H20 1 I N N cmcoon l r mooom NHz The process according to the present invention is generally carried out at an elevated temperature of from about 30C to about 120C, and preferably from about 50C to C.

As solvents there may be used water-miscible organic solvents, such as lower alcohols, dioxane and tetrahydrofuran; dimethyl formamide or dimethyl .sulphoxide can however also be used.

The hydroxylamine used in the reaction is preferably liberated in the reaction mixture by addition to the necessary quantity of a commercially available salt (preferably hydrochloride) of the necessary amount of a base (sodium hydroxide, potassium hydroxide, sodium acetate, etc.

The process is in general so carried out that, for example, lmole of hydroxylamine HCL-salt is dissolved hot in about 2 /2 1. of ethanol and mixed with one mole of base, for example sodium acetate (anhydrous), and 0.5 mole of a 3- acetimino-3H-1,2-dithiol, and the mixture heated atboiling point for about 1 to 2 hours with stirring.

It is possible for one to proceed so that the N-acyl compound produced is next cooled, filtered free from common salt and crystallized-out sulphur, isolated and finally hydrolyzed. Optionally, however, it may be expedient after completion of the reaction and the formation of the N-acyl compound to mix the reaction mixture directly with the customarily used amount of excess acid such as concentrated hydrochloric acid, sulphuric acid, etc. and to proceed with the hydrolysis at an elevated temperature, preferably at reflux temperature of the mixture.

After the hydrolysis has been completed, the amine is liberated in the usual way by addition of an alkali or alkaline earth metal hydroxide and isolated in a manner per se known for example by extraction with a solvent such as ether of benzene. The working-up of the initial products thus follows in accordance with known procedures.

The process of the present invention must be regarded as decidedly surprising, because the splitting off of the disulphide group was to be expected in the described reaction, while the formation of the 3-amino isothiazoles could, on the other hand, not be predicted.

The 3-aminoisothiazoles, derivatives and salts thereof of the present invention are useful not only for the fungicidal activity which they exhibit, which is useful in the treatment of fungi pathogenic to humans and animals, as well as the fungicidal activity which they exhibit against fungi pathogenic to plants, but the compounds of the present invention are also useful as intermediates in the preparation of plant protection agents.

Table 1 below shows by way of example the minimal inhibitory concentrations of a few representative compounds of the present invention against certain representative fungi. The experiments were carried out both in the presence and absence of serum.

TABLE 1 Minimal inhibition inhibition inhibition The following non-limitative examples in particular illustrate the present invention.

EXAMPLE 1 a. 13.9 (0.20 mol) of hydroxylamine. HCl (finely powdered) are dissolved hot in 500 ml ethanol and 16.4 g (0.20 mol) of sodium acetate (anhydrous) together with 20.9 g (0.10 mol) of 3-acetylimino-3H- 1,2benzodithiol are added. The mixture is boiled under reflux for 1.5 hours with stirring. After this time the mixture is cooled, precipitated sodium chloride and crystallized-out sulphur removed by suction filtration and the filtrate evaporated in vacuo. The 3-acetamino- 1,2-benzisothiazole formed crystallizes out on rubbing.

The compound forms yellowish prisms on recrystalliza- EXAMPLE 2 13.9 g (0.20 mol) of hydroxylamine. HCl (finely powdered) are dissolved hot in 500 ml ethanol and 16.4 g (0.20 mol) of sodium acetate (anhydrous) together with 20.9 g (0.10 mol) of 3-acetylimino-3H- 1,2-benzodithiol added. The mixture is boiled for 1.5 hours under reflux with stirring, and after this time mixed with 250 ml concentrated sulphuric acid and heated at boiling point for another hour.

The reaction mixture is mixed with carbon, filtered hot, and the filtrate evaporated to dryness in a waterpump vacuum. After treatment with excess sodium hydroxide (cca. 10 percent aqueous solution) the splitoff amine is taken up in ether and the ethereal solution dried. After removal of the solvent 3-amino-l ,2- benzisothiazole is obtained in yield of percent of theory.

M.p. 114C.

in a manner analogous to that set forth in Examples 1 and 2, the following compounds may be prepared from the following starting materials: 6-Chloro-3-acetamino-1 ,2-benzisothiazole, 177C, from benzodithiol 5-Chloro-7-methoxy-3-acetamino-4-methyl-1 ,2- benzisothiazole, M.p. 222C, from 5-chloro-7-methoxy-3-acetylimino-4-methyl-3H-l ,2-benzodithiol 3-Acetamino-5,7-dimethyl-1,2-benzisothiazole, colorless prisms (ethanol), m.p. 188C, from 3-acetylimino- 5 ,7-dimethyl-3H-l ,2-benzodithiol. 5-Nitro-3-acetamino-1,2-benzisothiazole, light yellow prisms (dioxane), m.p. 226C (Subl.), from 5-nitro-3- acetyl-imino-3H- l ,2-benzodithiol. 5-Phenyl-3-acetamino-isothiazole, m.p. C (Subl.), colorless prisms, from 5-phenyl-3-acetylimino3l-1-l,2- dithiol.

4,5 ,6,7-Tetrahydro-3-acetamino-1 ,2-benzisothiazole, m.p. 118C, from 4,5,6,7-tetrahydro-3 acetylimino-3 H-l,2-benzodithiol. 5,6-Dihydro-4l-1-3-acetamino-cyclopenta-[d]- isothiazole, colorless prisms (methanol), m.p. 126C, from 5 ,6-dihydro-4l-l-3-acetylimino-cyclopenta-[ d -3 H-1,2-dithiol. Y 4,5'-Dim'ethy1-3-acetamino-isothiazole, m.p. from 4,5-dimethyl-3-acetylimino-3H-1,2-dithiol.

6-chloro-3acetylimino-3H-1,2-

5-Methyl-3-acetamino-isothiazole, m.p. 160C (Subl.), from 5-methyl-3-acetylimino-3H-1,Z-dithiol.

4-Methyl-3-amino-isothiazo1e, colorless crystals,

m.p. 121C (Subl.), from 4-methyl-3-acetylimino- 3H-1 ,2dithiol.

5-Methy1-3-amin0-is0thiazole. HCl, colorless crystals, m.p. 142C from 5-methyl-3-acetylimino-3H-1,2- dithiol. 3-Amino-5 ,7-dimethyll ,2-benzisothiazole, 143C, from benzodithiol. 6-Chloro-3-amino-1,Z-benzisothiazole, (Subl.), from benzodithiol. 5-Ch1oro-7-methoxy-3-amino-4-methy1-1,2- benzisothiazole. HCl, m.p. 186C (Subl.), from 5 chloro-7-methoxy-3-acetyl-imino-4-methy1-3H- l ,2- benzodithiol, 4,5,6,7-Tetrahydro-3-amino-1 ,2-benzisothiazole, m.p. 177C, from 4,5 ,6,7 tetrahydro-3-acety1imino-3l-l- 1 ,2- benzodithiol. 5 ,6-Dihydro-4l-l-3-amino-cylcopenta-[ d -isothiazole, colorless prisms, m.p. 116C, from 5,6-dihydro-4H-3- acetylimino-cyclopenta-[ d]-3H-l ,Zdithiol. 4,5-Dimethyl-3-amino-isothiazo1e, colorless prisms, m.p. 99C, from 4,5-dimethyl-3-acetylimino-3H-1,2- dithiol.

What is claimed is:

l. A compound selected from the group consisting of m.p. 3-acetylimino-5,7-dimethyl-3H-1,2-

m.p. 156C 6-chloro-3-acetylimino-3H-1,2-

an isothiazole derivative of the formula:

wherein X is --COR in which R is alkyl of one to eight carbon atoms, and

R and R together with the carbon atoms to which they are attached are benzo substituted by up to three substituents selected from the group consisting of halogeno, alkyl of one to four carbon atoms, alkoxy of one to four carbon atoms and nitro.

2. The compound according to claim 1 which is 3- acetamino- 1 ,2-benzisothiazole.

3. The compound according to claim 1 which is 6- ch1oro-3-acetamino-1 ,2-benzisothiazole.

4. The compound according to claim 1 which is 5- chloro-7-methoxy-3-acetamino-4-methy1-1 ,2- benzisothiazole.

5. The compound according to claim 1 which is 3- acetamino-5,7-dimethyl-1 ,2-benzisothiazole.

6. The compound according to claim 1 which is 5- nitro-3-acetamino-l ,2-benzisothiazole. 

2. The compound according to claim 1 which is 3-acetamino-1,2-benzisothiazole.
 3. The compound according to claim 1 which is 6-chloro-3-acetamino-1,2-benzisothiazole.
 4. The compound according to claim 1 which is 5-chloro-7-methoxy-3-acetamino-4-methyl-1,2-benzisothiazole.
 5. The compound according to claim 1 which is 3-acetamino-5,7-dimethyl-1,2-benzisothiazole.
 6. The compound according to claim 1 which is 5-nitro-3-acetamino-1,2-benzisothiazole. 